Ganymede’s Shadow

During a close pass by Jupiter last February, the Juno spacecraft caught Ganymede’s shadow on the planet. The spacecraft was about 71,000 km above the cloud tops, only 6 to 7 % the distance between Jupiter and Ganymede.

An observer inside the oval shadow on Jupiter’s cloud tops would see a total eclipse of the Sun. Jupiter has four large moons (Ganymede, Io, Callisto, and Europa) that often pass between Jupiter and the Sun, so the moon shadows are often fall on the planet.

Image Credit—
Data: NASA / JPL / SwRI / MSSS
Image processing: Thomas Thomopoulos © CC BY

Listening to Ganymede

This animation provides auditory and visual presentations of data collected by the Juno spacecraft’s Waves instrument during a flyby of the Jovian moon Ganymede. The animation is shorter than the duration of the flyby because the Waves data is edited onboard to reduce telemetry requirements.

The abrupt change to higher frequencies around the midpoint of the recording occurs as the spacecraft moves from one region of Ganymede’s magnetosphere to another. The actual frequency range of the data is from 10 to 50 kHz. The animation audio has been shifted to a lower range audible to human ears.

Video Credit: NASA

Ganymede’s North Pole

On 26 December, 2019, the Juno spacecraft’s orbit around Jupiter brought it near the north pole of the ninth-largest object in the solar system, the moon Ganymede. The spacecraft’s Jovian Infrared Auroral Mapper (JIRAM) instrument took the first infrared images of the massive moon’s north pole.

Ganymede only moon in the solar system that is larger than the planet Mercury. It’s mostly water ice. It is also the only moon in the solar system with its own magnetic field. On Earth, the magnetic field provides a pathway for plasma (charged particles from the Sun) to enter our atmosphere and create aurora. Ganymede has no atmosphere to impede the progress of those charged particle, so the surface at its poles is constantly being bombarded by plasma from Jupiter’s gigantic magnetosphere. The bombardment has a dramatic effect on Ganymede’s ice.

The ice near both poles of the moon is amorphous. This is cause by the impact of the plasma on the surface. That pounding prevents the ice from having a crystalline structure.

Image Credit: NASA/ JPL / SWRI / ASI / INAF

Smog on Jupiter?

The Juno spacecraft took this image of Jupiter’s northern latitudes during a close approach 17 February, 2020. Two long, thin bands run through the center of the image from top to bottom. Juno has observed these streaks since its first close pass over Jupiter in 2016. They are layers of haze particles floating above the cloud. We’re unsure of what these hazes are made of, or how they form. (There are no known SUVs on Jupiter.) There’s been speculation that jet streams in the planet’s atmospher may influence the formation of the hazes.

Image Credit: NASA / JPL / SwRI / MSSS
image processing by Gerald Eichstädt

Jupiter’s Magnetic Field

This animation illustrates Jupiter’s magnetic field at a single moment in time. The Great Blue Spot, an-invisible-to-the-eye concentration of magnetic field near the equator, stands out as a particularly strong feature. The gray lines (called field lines) show the field’s direction in space, and the depth of the color on the planet’s surface corresponds to the strength of the magnetic field. Dark red and dark blue correspond to strong positive and strong negative fields, respectively).

Video Credit: NASA

So Long And Thanks For All The Fish

This sequence of images was taken on 29 October as the Juno spacecraft performed its 16th close flyby of Jupiter. Juno was between 18,400 and 51,000 km the planet’s cloud tops. A cloud in the shape of a dolphin appears to be swimming through the cloud bands along the South South Temperate Belt.

Image Credits: NASA / JPL-Caltech /SwRI / MSSS / Brian Swift / Seán Doran

Arthur Dent was unavailable for comment.

Clouds on Jupiter

This color-enhanced image was taken by the Juno spacecraft as it made its 16th close flyby of Jupiter. It was taken about 7,000 km above the cloud tops at a latitude around 40° N. The picture shows several bright-white “pop-up” clouds as well as an anticyclonic storm, known as a white oval.

Image Credits: NASA / JPL-Caltech / SwRI / MSSS / Gerald Eichstädt / Seán Doran

A Southern View of Jupiter

This extraordinary view of Jupiter was captured the Juno spacecraft as it moved away form the planet after twelfth close flyby..

Seeing Jupiter from the this far south causes the Great Red Spot to appear as if it is in Jupter’s north. It isn’t, but this new perspective demonstrates how different our view is when we step off the Earth and discover the three-dimensional nature of the Universe.

Image Credits: NASA / JPL-Caltech / SwRI / MSSS / Gerald Eichstäd / Seán Doran